Because portability is important in mobile terminals such as mobile telephone handsets, the size of display devices, such as liquid crystal displays is limited. Given this, there have been a mobile terminal connecting to an external display device and causing the display of an image generated thereby. As part of this situation, there has been a case in which, when a device having a touch panel as an external display is connected to a mobile terminal having a display of a different size, operation is possible from both the mobile terminal and the external display, with a device having one touch panel.
For example, Patent Document 1 discloses a technique for the purpose of operating an external display with a touch panel connected to a mobile terminal from the touch panel of the mobile terminal itself (refer to Patent Document 1).